A gas turbine engine can include a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
Rotors in the compressor section can be assembled from a disk that has a series of slots that receive and retain respective rotor blades. Another type of rotor is an integrally bladed rotor, sometimes referred to as a blisk. In an integrally bladed rotor, the disk and blades are formed from a single piece or are welded together as a single piece. Vanes are provided between the rotors to direct air flow. One type of vane is cantilevered from its radially outer end. The inner end may have a shroud. One or more seals can be provided at the inner end shroud; however, a small amount of gas path air downstream of the vanes can enter a cavity under the inner end shroud and escape past the seals.